The present invention relates to a self-inductance element comprising a coil winding on a rectilinear magnetic core.
Such an element is used in cable television distribution systems.
An element as defined in the opening paragraph above is known from EP 0 642 142. (U.S. Pat. No. 5,767,759) According to this document, a coil comprises a single winding wound on a magnetic core formed by a plurality of ferrite cylinders placed and to end.
A cable television distribution system comprises antennas, amplifiers, cables and distributors; a self-inductance element placed in these distributors enables to pass comparatively strong 50 Hz DC or AC supply currents so as to supply the amplifiers with power via the cables from power supplies situated in a building. The range of frequencies flowing through these systems being very wide, it is hard to achieve that this element has both a high impedance at the lowest frequencies (5 MHz) and no resonance at the highest frequencies. In addition, when a strong AC current passes through the element, there is a risk of a parasitic modulation phenomenon occurring at 50 Hz due to a periodic saturation of the magnetic core.